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Room temperature reaction between polycrystalline Ni/Al bilayers deposited in ultrahigh vacuum

Journal Article · · Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (USA)
DOI:https://doi.org/10.1116/1.577045· OSTI ID:7109130
; ;  [1]
  1. Brookhaven National Laboratory, Upton, New York 11973 (US)

The growth of polycrystalline Ni--Al bilayers deposited in ultrahigh vacuum ({ital P}{lt}10{sup {minus}9} Torr), and their modification by annealing are studied by Auger and photoemission spectroscopy. At room temperature, Ni deposition on Al causes a chemical shift of the 68-eV Al Auger line and photoemission shows that the Ni 3{ital d} valence-band states for thin Ni overlayers are narrower and shifted away from {ital E}{sub {ital f}} when compared to Ni metal. For Al deposited on Ni, the 68-eV Al Auger line also undergoes a chemical shift and photoemission shows the Ni 3{ital d} valence band is modified by the appearance of a new state at higher binding energy. Based on comparisons with photoemission and Auger data presented by others for Ni--Al intermetallic compounds, and photoemission, ion channeling and ion scattering results published for the chemically similar Pd--Al system, we conclude that polycrystalline Al and Ni films partially intermix and form a NiAl{sub 3}-like intermetallic compound at room temperature. We believe this Ni--Al compound may be found at the thin-film interface, at grain boundaries or on the surface of 3-D Ni or Al islands. Heating Ni/Al bilayers at 600 K promotes Al out diffusion and heating at higher temperatures leads to the formation of other Ni--Al compounds.

DOE Contract Number:
AC02-76CH00016
OSTI ID:
7109130
Journal Information:
Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (USA), Journal Name: Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (USA) Vol. 8:1; ISSN JVTAD; ISSN 0734-2101
Country of Publication:
United States
Language:
English